Gelatin coating compositions



United States Patent 3,306,749 GELATIN COATING COMPOSITIONS William J. Knox, John F. Stenberg, and Charles V.

Wilson, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Original application Sept. 20, 1962, Ser. No. 225,108. Divided and this application Mar. 4, 1965, Ser. No. 437,273

Claims. (Cl. 96-94) This application is a divisional of our application Serial No. 225,108, filed September 20, 1962.

This invention relates to proteinaceous compositions particularly of gelatin or casein, having therein as a coating aid an acyl derivative of iminodiacetic or iminodipropionic acid.

In the photographic industry it is often desirable that various protein coatings, either the photographic emulsion itself or other coatings, exhibit both good surface slickness and good developer wettability.

In the coating of film or paper in the making of photographic products with a gelatin layer, such as of a photographic emulsion or some other gelatin coating composition, it is desirable that the application of the composition to the surface to which it is supplied be uniform, particularly when the coating is carried out at production speed. The absence of coating aid often results in defects such as evidenced by repellencies, pencil line streaks or the like. Saponin has been employed as a coating aid in this connection but this material differs markedly from batch to batch in quality and composition. This may not only adversely affect a photographic emulsion but in some instances may give little or no improvement in coating properties.

Several synthetic materials have been referred to in the prior art as being useful as coating aids in gelatin compositions. Sometimes, however, these coating aids leave something to be desired such as in coating methods in which several coatings are applied to a support simultaneously, such as in the procedure described in US. Patent No. 2,761,791 of T. A. Russell.

One object of our invention is to provide proteinaceous coating compositions from which may be obtained blemish-free coatings having good surface slickness and developer wettability when those compositions are laid down to form a layer or layers upon a support. Another object of our invention is to provide gelatin and casein coating compositions which are useful for application over paper or film base support or over previous gelatin coatings residing upon a support. A further object of our invention is to provide proteinaceous coating compositions having therein alkali metal salts of acyl derivatives of iminodiacetic acid and/or iminodipropionic acid in which the acyl radical is 12-18 carbon atoms. Other objects of our invention will appear herein.

We have found that water soluble salts of acyl derivatives of iminodiacetic or iminodipropionic acid, the acyl being of 12-18 carbon atoms, are useful as coating aids in aqueous proteinaceous coating compositions from which layers may be obtained having good surface slickness and good developer wettability when such composi tions are applied either over a support or over a previous proteinaceous coating. We have found that coatings may be applied from these compositions which are substantially free of defects such as pencil line streaks, mottle and general streakiness and the like, such as frequently characterizes coatings particularly in multiple layer hopper coating operations.

The coating aids which we have found to be useful in proteinaceous compositions are those having the formula:

3,306,749 Patented Feb. 28, 1967 ice in which x=12, R is a 11-17 carbon hydrocarbon radical and M is a cation which contributes to the water solubility of the coating aid, for instance ammonium, sodium, potassium or the like.

Some compounds'which are useful as coating aids in accordance with our invention are N-lauroyl-N-carboxymethyl glycine, N-oleoyl-N-carboxymethyl glycine, N-dodecyloxybenzoyl-N-carboxymethyl glycine, N-(2,4-di-tertiary-amyl phenoxy acetyl) N carboxymethyl glycine, N-stearoyliminodiacetic acid, N-stearoyliminodipropionic acid, N-myristoyliminodiacetic acid, N-palmitoyliminodiacetic acid, and the like in the form of their alkali metal or ammonium salts. We have found in general that the coating aids should be used in a concentration between about 0.2 and 2.7 parts per parts of the protein, e.g. gelatin or casein in the composition.

Although the protein compositions in accordance with our invention are useful in applying single layers, they are especially useful in the laying down of a plurality of layers in a simultaneous coating operation in a multiple coating technique such as on the order of that described in US. Patent No. 2,761,791 of T. A. Russell. Instead of a multiple layer operation in which the layers are simultaneously applied, the plurality of layers may be applied in sequence such as by coating one layer over a previous gelatin or casein layer either by a wet-on-wet coating operation or by a wet-on-dry procedure. The following examples illustrate coating procedures employing compositions in accordance with our invention:

Example 1 Gelatin-silver halide photographic emulsions containing N-lauroyl-N-carboxymethyl glycine (sodium salt) in amounts of 0.25, 0.5 and 1.0 gram per pound of emulsion, respectively, were variously applied to paper supports therefor by means of a hopper technique. The coatings of the various emulsions showed good developer wettability properties and smooth coatings of good quality were obtained.

Example 2 Gelatin-silver halide photographic emulsion containing in various proportions as a coating aid the disodium salt of N-oleoyl-N-carboxymethyl glycine was applied to paper by means of a hopper technique, the concentrations ranging from 0.3 to 1.0 gram per pound of wet emulsion. The photographic paper obtained had good photographic properties, exhibited good smoothness and was free of surface defects.

Example 3 Gelatin-silver halide photographic emulsion containing, in various proportions, N-dodecyloxybenzoyl-N-carboxymethyl glycine (sodium salt) as a coating aid was applied to paper by means of a hopper technique. The concentrations of coating aid used were 0.13, 0.25, 0.5 and 1.0 gram per pound of wet emulsion. Each of the coatings were found to have good photographic properties and a product was obtained having good surface smoothness.

Example 4 Gelatin-silver halide photographic emulsion containing as a coating aid therein in varying proportions the disodium salt of N-(2,4-di-tertiary-amylphenoxyacetyl)-N carboxymethyl glycine was coated onto paper by a hopper technique. The coating aid was used in proportions of 0.13, 0.25, 0.5 and 1.0 gram per pound of wet emulsion. Smooth coatings were obtained having good photographic properties and freedom from surface defects.

In each of the examples given each pound of composition contains 37 grams of gelatin or casein. The coating aid is present in an amount within the range of about 1.9 to about 2.7 parts thereof per 100 parts of the gelatin or protein in the coating composition in which it is used.

The invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove, and as defined in the appended claims.

We claim:

1. A coating composition comprising an aqueous solution of a protein containing therein about 0.2 to 2.7 parts per 100 parts of the protein of coating aid represented by the formula: I

RCON (CH COOM] 2 in which x=1-2, R is a member selected from the group consisting of an open chain hydrocarbon radical having 1l-17 carbon atoms, dodecyloxyphenyl and tert-arnyl- C H 2- tert-arnyl and M is a cation contributing to water solubility of the coating aid.

2. A coating composition comprising an aqueous solution of gelatin containing as a coating aid therein about 0.2 to 2.7 parts per 100 parts of gelatin of water soluble salt of acyl iminodiacetic acid, the acyl group having the formula RCO, wherein R has the meaning set forth in claim 1.

3. A coating composition comprising an aqueous solution of gelatin containing as a coating aid therein about 0.2 to 2.7 parts per 100 parts of gelatin of water soluble salt of acyl iminodipropionic acid, the acyl group having the formula RCO, wherein R has the meaning set forth in claim 1.

4. A gelatin-silver halide photographic emulsion containing therein about 0.2 to 2.7 parts per 100 parts of gelatin of coating aid represented, by the formula:

RCON[(CH COOM] wherein x, R and M have the meaning set forth in claim 1.

4 5. A photographic product comprising a support and a proteinaceous layer thereon which layer contains about 0.2 to 2.7 parts per parts of protein of compound having the formula:

wherein x, R and M have the meaning set forth in claim 1.

6. A photographic product comprising a support containing thereon a plurality of proteinaceous layers each of which contains about 0.2 to 2.7 parts per 100 parts of protein of compound having the formula:

References Cited by the Examiner UNITED STATES PATENTS 2,240,471 4/ 1941 Swan 117-164 2,919,197 12/1959 Duin 260404 3,038,804 6/1962 Knox et al. 96111 3,042,522 7/1962 Ben-Ezra 9694 3,133,816 5/1964 Ben-Ezra 9694 NORMAN G. TORCHIN, Primary Examiner.

J. TRAVIS BROWN, Examiner. 

1. A COATING COMPOSITION COMPRISING AN AQUEOUS SOLUTION OF A PROTEIN THEREIN ABOUT 0.2 TO 2.7 PARTS PER 100 PARTS OF THE PROTEIN OF COATING AID REPRESENTED BY THE FORMULA: 